In the pre-lecture we saw that FT-IR spectroscopy probes molecular vibrations, treating the molecule like a series of masses on springs. In this model, the spring constant k is related to the strength of the bond. The equation describing the vibrational frequency of a mass-spring system is:

v= 1/ 2π √K/μ

Where v is the vibrational frequency, k is the spring constant and u is the reduced mass. From this justify the following trend in IR absorptions for alkyl halides.

Bond Absorption Position(cm^-1)
C-F 1000-1400
C-Cl 600-800
C-Br 500-600
C-l 500

Answer asap need by wednesday morning explain how a buffer works, using an ethanoic acid/sodium ethanoate system including how the system resists changes in ph upon addition of a small amount of base and upon addition of a small amount of acid respectively. include the following calculations in your i. calculate the ph of a solution made by mixing 25cm3 0.1m ch3cooh and 40cm3 0.1m ch3coo-na+. [ka = 1.74 x 10-5 m] ii. calculate the ph following the addition of a 10cm3 portion of 0.08 m naoh to 500cm3 of this buffer solution. iii. calculate the ph following the addition of a 10cm3 portion of 0.08 m hcl to 200cm3 of the original buffer solution.